Stretching machine



y 5, 1933. R. L. GRIFFIN ET AL 1,919,649 I STRETCHING MACHINE Filed March 51 1928 Sheets-Sheet 1 y Z5, 1933- R. GRIFFIN ET AL- 1,919,649

' STRETCHING MACHINE Filed March 31, 1928 3 Sheets-Sheet 2 July 25, 1933.

R. L. GRIFFIN ET AL STRETCHING MACHINE Filed March 31, 1928 E A m 3 Sheets-Sheet 3 W WM Patented July 25, 1933 v i arsnf'r "rt-a I ROGER L. emrrmnnn JAMES ronEIL, on rrieiaoqsyjraassacirusn rrs, Assieuons TO A. o. LAVIRENCE LEATHER COMPANY, or BOSTON, MASSACHUSETTS, a CORPORA- TioNoF M IN s'rnnrcnme Meonrnn Application filed march 31, 1928. serial No. 266,365.

The present invention relates to stretch ing. machines and more particularly to power operated machines designed especially for stretching leather, hides, or skins,

Oneof the objects .of the present invention is to provide a power operated machine of simple and inexpensive construction for stretching leather hides or skins or other like material in an expeditious and exact manner. f Another object of the invention is to provide a power operated machine whereby varying amounts of stretch may be parted to the material in different d rections and in different portions thereof, according to the skill and judgment of the operator and dependent upon the size and character of the material and the result desired. i

With these and otherobjects in View, as will'be apparent to those skilled in the art, the present invention consists in the'devices and combination of deviceshereinafter described and claimed, I

.lustrated in the accompanying drawings in which Fig.1 is a top plan view of the-machine showing a corner portion of the expansibl'e frameto which the hide or other material to be stretched is attached; Fig. 2 is a front elevation of the machine with the expansible frame in position and a portion thereof shown in section; Fig.3 is a top plan view of the extensible frame showing the manner of attaching a hide; Figs. 4 and 5 show a top andside View, respectively, in detail of the toggle,toggle cord, and

cleat used in securing ahide to the frame;

Fig. 6 is adetail elevation of a portion of the machine showing one of the dogs which engage the'frame to which the hide is attached, together with its actuating screw and limit switches; and Fig. 7 is a schematic diagram of motors, controls, and associated circuits employed in actuating the machine.

The apparatus illustrated in the drawings comprises, briefly, an expansible frame within which the hide is secured, and a machine for expanding, such frame and thereby stretching the hide,the frame-having proframe; is held The invention in its preferred form is ilthen'secured in position by 'tiglite ning the nuts.

-era-1 horizontal members 22 conneCtedtovision for maintaining its expanded: condition so that it may be removed from the machine for thedrying .or other treatment of p 7 the hide and the expanding of another frame by the machine. 1 f TI Therexpansible' frame is shown in Fig.3 and comprises .the four frame members or bars 11, having at each end the overlapping, longitudinally arranged slots l2,"'thr.oug h which extend the bolts 18 with suitable washers and. lockingnuts. The slots 12 perniit the expansion andhontraction of the frame as desired when th'e'nutsare loosened. Thereafter, by tightening the nuts the fixedly in J the adjusted position. v p I The hlde or similar material to be stretched is fastened inside the framexloy on the framezmembers;

:- Preparatory to mounti'ng a hide. in the frame, the latter will be contracted, preferably to its minimum size so as to permit: a

sufficient range :ofexpansion to provide the desired degree of'stretch The parts are so The hide is next mounted in the frame by means of the toggles and cords, the

latter being drawn and fastened with the desired, tension so as to extend the hide flat and smooth under auniform low tenable shoulders or'dogs which engage with the inner edges of all four members of the/ frame and are moved apart .by [means of threaded shafts driven by. electric; motors.

This mechanism is carried upon the machine frame which is composed of the sev- 9.5 gether with angle brackets and having corner'posts 24. Secured upon the top of the 7 frame members are the flat bearing supports the several threaded sliafts. These are four to j in number and are arranged horizontally in the form of a square with their ends overlapping. Two of these shafts 30 and 32 are parallel to one another and are located on opposite sides of the machine, being driven by a single motor 34 through reduction gearing 36 and sprockets 38 and chain lO. The other pair of shafts, 42 and ll, at right angles to the first mentioned pair, are driven each by its own independent motor 46 and 48, respectively, with similar tatedin the opposite direction the dogs will be drawn together. The threads on shafts 30 and 32 are so arranged that when the motor 34lis operated in one direction all four of the dogs on these shafts move outwardly to the ends, and when the motor is reversed they move inwardly.

In order to maintain the dogs in proper vertical position during their inward and outward movement along the threaded shafts, each dog is provided with a depending foot 56 having a circular hole 58 to receive the guide rod 60 mounted in the vertical supports 62 and 641'.

The expansible hide-carrying frame is supported above the several shafts and their actuating mechanism upon the horizontal arms 66 extending outwardly near the cor ners of the machine. Preferably these arms are arranged in pairs on opposite sides of the machine so that the two opposite bars only of the expansible frame'will be supported, the other two bars beingcarried' by the'first mentioned bars. This arrangement is desirable owing to the fact that the two pairs of bars do not lie in the same plane.

In the stretching of many materials the amount of stretch desired will vary, not only in direction but also indifferent portions, according to the character of the material, its intended use, etc. In the stretching of hides,'difl"erent amounts of stretching will ordinarily be required along the backbone, across the neck, and across the butt.

Accordingly, in the illustrated embodiment of the present invention, the motors imparting stretch to these parts are under separate and independent control whereby any desired extent of stretching movement may be given through. the dogs actuated by one motor without affecting the dogs actuated by either of the other motors. Furthermore, in order to avoid loss-of time these motor c n r ls a e so ar a g d that all thei motors may be simultaneously operated if desired, or any two of them. For the same reason the idle or reverse rotation of the motors to return the dogs to their inward or initial position is simultaneously effected and preferably through a single or common control.

The circuits and controls are illustrated schematically in Fig. 7, and comprise a three phase current supply indicated by the leads A, B, and C; the three motors marked D, E, and F; the three forward magnetic starters, one for each motor, indicated at FMS, FMS and F the operating magnets therefor FOM, FOM and FOM three reverse magnetic starters EMS, RMS and EMS; the operating magnets therefor ROM, ROM and ROM; three push button controls for the forward starters, one for each motor, indicated at PB, P13 and P13 a single'push button control for all three reverse starters P13 three limit switches for forward movement, one for each motor, FLS, FLS and FLS and a similar number of reverse limit switches RLS', RLS and RLS".

The electrical connections between these various parts are clearly shown on the diagram and need not be here described in detail. The limit switches are located as shown in Fig. 6, the forward switch FLS' being placed at or near the outward limit of movement of the dog 54 so that the depending foot 56 will engage and actuate the switch to stop the motor and prevent further outward movement of the dog. Similarly the reverse limit switch RLS is placed at or near the limit of the inward or reverse movement of the dog.

Ordinarily the forward or outward limit switch is not brought into action, the operator having given sufficient stretching movement tothe hide and stopped the motor before the extreme outward position is reached by the dog. The inward or reverse limit switch, however, operates on each'reverse movement of the motor, being the only means for stopping such reverse movement.

The push button controls are located at some convenient position for the operator where he can stand and observe the stretching as it progresses. The connection through each of the forward push buttons is such that each must be held depressed in order to maintain its operating magnet energized and its forward magnetic starter in operation to supply current to its motor. Upon release of' a button, the motor controlled thereby immediately stops, but may be started again by depressing its proper button if further stretching is desired.

The connections through the single reverse button and the reverse operating magnets are such that once the button is depressed and the magnets energized, they will remain I stretched.

While the motors are stationary and the frame has been locked in-its expanded position, the operator has only to depress momentarily the singlereverse button, whereupon all three motors are SQt lIl reverse operation and each continues until it is independently stopped by its reverse limit switch.

In the operation of the machine the hide is first toggled,that is, mounted in the cxpansible frame by means of the toggles and their attaching cords, the frame being contracted at this time. The frame is then placed upon the machine with the backbone of the hide, i. e. its longitudinal axis from neck to tail, parallel to the pair of shafts which are actuated by the single motor and the clamping nuts are loosened.

The operator nextdepressesthe button controlling the motor and the dogs engaging the bars opposite the neck and tail exert-a preliminary stretching lengthwise of the hide. When sufficient preliminary stretch has been imparted, the button is released and the other buttons are depressed to stretch the hide transversely at the neck and the butt. This may be done simultaneously or consecutively as the operator de-' sires, and further-stretching may be imparted to the hide in any direction or amount as the operator in his judgment shall deemadvisable, until the hide has been properly frame is held expanded, the operator tightens the nuts upon the corner bolts and thus locks the frame in its expanded condi tion. The frame and its hide are then removed for' drying or other treatment. A momentary depression of the reverse button by the operator brings the parts automatically back to their original position ready for another frame and hide.

Thus a hide may be stretched by powerstret-ching devices in an expeditious and exact manner, under the full control and judgment of the operator, according to the character of the hide, its intendeduse, etc.

Vhile the present invention has been shown and described as embodied in a ma chine for stretching hides, it is to be understood that it is not necessarily limited thereto but may be embodied in machines for stretching other materials. Nor is the present invention limited to the particular forms and arrangements herein shown and described but may beembodiedin other and different forms and combinations withln'the language of the claims.

Having thus described'the invention, what i is claimed is: I g,

1. A stretching machine having,'in combination, a pair of threaded shafts disposed at right angles to one another, threaded dogs on the shafts, amotor for eachshaft, and controlling devices for independently controlling the operation of each motor in one direction and for commonly controlling the operation of both motors in the opposite direction.

2. A stretching machine havin in combination, a threaded shaft, a motor for ac -v tuating the same, a' threaded dog mounted on the shaft, a swltch for controlling the starting and stopping of the motor when the shaft is being actuated during thestretching operation, a reverse switch for setting the motor in operation to actuate the shaft for its idle or return operation, andv a stopping switch for automatically stopin the motor on the com letion of such b idle operation. I

3. A stretching machine having, in combination, a plurality of shafts, means having screw connections with the shafts for impartinga stretching action to the material to be stretched, and power-driven connections under the control of the operator for operating a portion of said shafts simultaneously, and others of said shafts independently to vary the extent and direction of the stretching action. v

4:. A. stretching machine having, in combination, horizontally extending supports on opposite sides of the machine for supporting an expansible frame, two pairs of horizontally disposed shafts positioned below the plane of said supports, the shafts of one pair being parallel and at right angles to the parallelshafts of the other pair, the shafts of each pair being widely spaced apart, devices actuated by the shafts for engaging andexpanding the frame, and power actuated means for rotating each pair of shafts independently of the, other pair in one direction, and both pairs simultaneously in the-other direction.

5. A stretching machine having, in combination, devices for imparting stretching action to the work, Dower driven imparting longitudinal and transverse movements to said devices, and control mechanism for said means for independently controlling the longitudinal andtransverse advance movements thereof and for commonly having in combination, devices for engaging each member of the frame at a plurali y of means for ing each independently of the other for actuating a portion only of the said devices for each of the other pair of frame members, whereby different portions of the latter pair of frame members may be moved different distances outwardly to vary the stretching effect at different portions of the frame.

ROGER L. GRIFFIN. JAMES T. ONEIL. 

